Labconco FreeZone Plus 4.5 Liter and FreeZone -105 C Cascade Freeze Dry Systems 73870 Series - Manual (Page 36)

Chapter 7: Troubleshooting
Product Service 816-333-8811 or 1-800-522-7658 32
If vacuum problems continue, consider obtaining a second vacuum gauge
capable of reading a vacuum of 0.010 mBar. It is often useful in determining
if the vacuum pump is operating properly and the vacuum sensor reading is
accurate.
4.
Isolate the pump by disconnecting the vacuum hose from the freeze
dryer. Deadhead the pump by inserting the vacuum sensor from a
secondary vacuum gauge into the end of the vacuum hose and observe
the vacuum reading obtained. Confirm that the pump is capable of
achieving an ultimate vacuum less than 0.010 mBar or approximately
10 microns. If an inadequate vacuum reading is obtained, the pump
has most likely failed and may need to be replaced or rebuilt.
II. Gaskets, Tubing, Connections, Sample Valves
1.
Check all sample valves on the drying chamber/manifold and ensure
all valves are closed or in the vent position. Check to ensure all
fittings are tight and sealed properly against the chamber. Inspect
valves for cracks or cuts.
2.
Inspect gasket(s) for cracks or defects. Ensure the gasket is clean.
Apply a thin coat of vacuum grease to the gasket. Keep in mind too
much vacuum grease can actually cause leaks.
3.
Check the drain line and ensure the drain plug is installed and the tube
appears to be in good condition.
4.
Check all rubber vacuum tubing for signs of deterioration or cracking.
5.
Check all connections and make sure they are secure and leak tight.
6.
When checking the sample valves, pull as much vacuum as possible.
If a vacuum indication is displayed, wiggle or rotate the valves and
watch the gauge for any fluctuations. Fluctuations can indicate a
potential vacuum leak. If the valve seems to be in good condition,
remove the valve and apply a thin coat of vacuum grease to the stem
and the outside sealing surface of the valve body, and reinstall the
valve. DO NOT APPLY VACUUM GREASE TO THE SAMPLE
VALVE GASKETS, WHICH SEAL TO THE WALL OF THE
DRYING CHAMBER. If the valve still seems to be the source of
the problem, remove the valve and stopper the hole with a rubber
stopper. Continue checking the other valves.
7.
Make sure that the sample valve bulkhead nuts are tight. Either
tighten by hand or use the wrench supplied with chambers. To use
the wrench, first remove the knob and stem assembly and also the
valve body. The pins on the wrench fit into the round holes of the
nut. The nut should be snug but avoid over tightening. Replace the
valve body and knob and stem assembly.